1. Performance Chemicals

• Acid Neutralization: Triethylamine hydrochloride acts as a source of triethylamine, which can then neutralize acids formed during a reaction. For example, it's frequently used in the synthesis of esters and amides from acyl chlorides, where triethylamine hydrochloride is formed as a byproduct. 
• Catalysis: It been used as a catalyst in certain reactions, such as the Friedel-Crafts reaction, to facilitate the formation of a desired product. 
• pH Adjustment: In some cases, it is used to adjust the pH of a reaction mixture, particularly in situations where a slightly acidic or near-neutral pH is needed.
• Semi-synthetic Antibiotic Side Chains: Triethylamine hydrochloride is also used in the synthetic manufacturing of semi-synthetic antibiotic side chains.

2. Pharmaceuticals

• Base and catalyst: Triethylamine hydrochloride acts as a base and catalyst in various organic transformations, including acylation, alkylation, and condensation reactions. It facilitates nucleophilic substitutions, which are crucial in the synthesis of many pharmaceutical compounds.
• Protein Purification: Triethylamine hydrochloride is used as a competing base in protein purification processes, helping to separate acidic, basic, and neutral drugs. It's also used in reverse-phase liquid chromatography for separating proteins and other biomolecules.

3. Polymers & Resins

• Byproduct in Synthesis: TEA•HCl is often a byproduct in the synthesis of carbonate monomers, making its catalytic properties useful in utilizing this readily available compound.

4. Agrochemicals

• Reagent in Synthesis: Triethylamine hydrochloride is frequently used as a reagent in the synthesis of various agrochemicals, including herbicides, insecticides, and fungicides. 
• Quaternary Ammonium Compounds: It plays a role in the production of quaternary ammonium compounds, which are often used as active ingredients or adjuvants in pesticide formulations.

5. Paints, Coatings & Adhesives

• Neutralizing Agent: Triethylamine hydrochloride is used to neutralize acidic groups (like carboxyl groups) in anionic stabilized waterborne resins, which are commonly found in paints. This helps in creating stable and homogeneous paint formulations.
• Catalyst: It acts as a catalyst in the curing of epoxy and polyurethane systems, which are crucial components in many paints and coatings.
• Water-borne Polyurethane Dispersions: Triethylamine hydrochloride is used in the production of these dispersions, which are used in various coatings.